See online research publication

Wild bee diversity is declining worldwide at unprecedented rates, and steps must be taken to conserve them--and not just those that are the main pollinators of agricultural crops, agreed 58 bee researchers in a study published today (June 16) in Nature Communications, an open-access journal based in London.

"This study provides important support for the role of wild bees to crop pollination through a comprehensive global summary,” said co-author and pollination ecologist Neal Williams, associate professor in the UC Davis Department of Entomology and Nematology. “At the same time, we found that in any one region, much of the pollination services from wild bees to a given crop come from just a few species, thus we need to be careful about using a simplistic economic ecosystem-services argument for biodiversity conservation and maintain actions that target biodiversity as specific goal. "

Wild bees, or non-managed bees, include bumble bees (genus Bombus), sweat bees (genus Lasioglossum) and small carpenter bees (genus Ceratina).

The study, led by David Kleijn of Wageningen University, The Netherlands, found that of the almost 80 percent of crop pollination provided solely by wild bees, only 2 percent are by the most common species. This indicates that the benefits of conserving only economically important organisms are not the same as the benefits of conserving a broad diversity of species, the researchers said.

The paper, “Delivery of Crop Pollination Services is an Insufficient Argument for Wild Pollinator Conservation,” is online at http://www.nature.com/naturecommunications. Among the co-authors are native pollinator specialist Robbin Thorp, distinguished emeritus professor of entomology at UC Davis, and conservation biologist Claire Kremen of UC Berkeley, a longtime associate of the UC Davis Department of Entomology and Nematology.

“My role in this paper was through my collaborations with Neal Williams and Claire Kremen in their research projects on crop pollination by native bees,” Thorp said. “My identifications of the bees they sampled, provided the raw data for the calculations performed on the diversity and abundances of the bees pollinating the crops they studied.”

“There is compelling evidence that more diverse ecosystems deliver greater benefits to people, and these ecosystem services have become a key argument for biodiversity conservation,” the researchers wrote in their abstract. “However, it is unclear how much biodiversity is needed to deliver ecosystem services in a cost-effective way. Here we show that, while the contribution of wild bees to crop production is significant, service delivery is restricted to a limited subset of all known bee species. Across crops, years and biogeographical regions, crop-visiting wild bee communities are dominated by a small number of common species, and threatened species are rarely observed on crops.”

“Dominant crop pollinators,” they pointed out, “persist under agricultural expansion and many are easily enhanced by simple conservation measures, suggesting that cost-effective management strategies to promote crop pollination should target a different set of species than management strategies to promote threatened bees. Conserving the biological diversity of bees therefore requires more than just ecosystem-service-based arguments.”           

The researchers analyzed data from more than 90 studies on five continents, including Europe and North America. They concluded that the higher levels of biodiversity provide greater benefits to the functioning and stability of ecosystems, with some functions also being “economically beneficial” for humans.

Kleijn and his colleagues studied 785 species, analyzing which provide the best economic returns from crop pollination. They found that wild bee communities contribute an average of more than $3,251 per hectare (2.471 acres) to the production of crops, and that they provide the same economic contributions as managed honey bee colonies. However, they also noted that the majority of crop pollination services provided by wild bees are accomplished by only a small subset of the most common species.

“Across the 90 studies, we collected a total of 73,649 individual bees of 785 species visiting crop flowers,” the authors wrote. “Although is an impressive number, it represents only 12.6 percent of the currently known number of species occurring in the states or countries where our studies took place. When we consider only bee species that contribute 5 percent or more to the relative visitation rate of any single study, the percentage drops to 3 percent of the species in the regional species pool. Yet these 2 percent of species account for almost 80 percent of all crop visits.”

These results suggest that conservation efforts targeted directly at a few species providing the majority of ecosystem services, such as crop pollination, would represent a good strategy if the goal is to improve economic returns. However, they said such a strategy is unlikely to be compatible with conserving threatened species and biological diversity “if the goal is to improve the functioning and stability of ecosystems.”

Williams worked with Kleijn and Winfree of Rutgers University New Brunswick, N.J., to conceive of some of the approaches used, particularly suggested looking at the abundance distributions of crop bees within the larger species pools of the region to understand whether the most important crop pollinators species are simply the common bees overall. 

Williams and Kremen also contributed to the manuscript, from the early drafts to the final versions.

Link to online research paper

In observation of National Pollinator Week, the UC Davis Department of Entomology and Nematology has scheduled an open house at the Häagen-Dazs Honey Bee Haven from 5:30 to 7 p.m., Friday, June 19.

Activities will include bee observation and identification, honey tasting, sales of native bee houses to support the haven, and information about low-water plants.

The garden, planted in the fall of 2009, is located on Bee Biology Road, next to the Harry H. Laidlaw Jr. Honey Bee Research Facility.

The garden was founded and "came to life" during the term of interim department chair, Professor Lynn Kimsey, director of the Bohart Museum of Entomology, who coordinated the entire project. It is now managed by Chris Casey, staff director, and Extension apiculturist Elina Niño , faculty director.

Kimsey was singled out for her work when the Pacific Branch of the Entomological Society of America honored her and four others--"The Bee Team"--with the 2013 outstanding team award.

A Sausalito team--landscape architects Donald Sibbett and Ann F. Baker, interpretative planner Jessica Brainard and exhibit designer Chika Kurotaki--won the design competition.

Native pollinator specialist Robbin Thorp, distinguished emeritus professor of entomology, has found more than 85 species of bees since its inception.

For more information on the garden, see the haven website.  This includes a list of plants. The history of the garden is chronicled here. 

DAVIS--Margaret “Rei” Scampavia, a doctoral candidate who studies with major professors Neal Williams and Edwin Lewis in the Department of Entomology and Nematology, won first place for her research poster at the recent UC Davis Bee Symposium, held in the Robert Mondavi Center for Wine and Food Science. 

Scampavia's  poster,  “Farming Practices Affect Nest Site Selection of Native Ground Nesting Bees,” won her the $1500 prize. The Henry J. Kaiser Family Foundation generously provided the funding.

Two other graduate students in the Neal Williams' lab won second and third place. Jennifer Van Wyk placed second for her poster on “Wet Meadow Restoration Buffers the Impact of Climate Change: Pollinator Resilience During the California Drought” and Leslie Saul-Gershenz, who also works with professor Steve Nadler, placed third for her poster on “Native Bee Parasite Shows Multitrait, Host Specific Variation and Local Adaptation.” Van Wyk received a $1000 prize and Saul- Gershenz, $500.

“Availability of foraging and nesting habitat potentially limits native bee range, which affects where pollinator services occur,” Scampavia wrote in her introduction. “Prior studies focus on how foraging habitat influences bee distribution, but few consider nesting limitations. Understanding how different soil properties affect native bee nest site preference can help predict where these nests will be found in agricultural landscapes, as well as whether particular farming practices could affect the health of nesting bees.”

Her objective: “to determine whether tillage, irrigation and application of pesticides impact nest site selection using a controlled choice assay.”

Scampavia examined nesting in experimental plots in Davis in 2013 and 2014. She measured the nest initiation in each of the four soil treatment groups with soil emergence traps. The treatment groups were (1) tilled, irrigated, esfenvalerate applied (2) tilled, irrigated (3) tilled only (4) irrigated only and (5) negative control. Esfenvalerate, a synthetic pyrethroid, is commonly used for pest management in California.

She examined the nests of bees in four genus categories: Lasioglossum, Halictus, Svastra and Melissodes.

Scampavia concluded “The two soil treatments that positively influenced nest initiation (tillage and irrigation) would be found in actively farmed areas, rather than fallow fields or field margins. If the presence of insecticide residues or tillage affects offspring survival, these results suggest that bees nesting in agricultural areas are faced with an ecological trap that could negatively affect development and overwintering survival. Providing strips of bare, tilled and irrigated soil in early spring in field margins or hedgerows could be one way to create attractive pesticide and late-season tillage-free shelters in which native bees could nest.”

Prior to coming to UC Davis, Scampavia worked for the U.S. Forest service as a biological technician, studying pollinator visitation to rare plants of the Mojave Desert. She also volunteered at Scripps College (Jupiter, Fla.) as a planner and coordinator for large education outreach events.

Her current research deals with isolating and identifying specific soil attributes that affect nest site selection in bee species, and how these attributes impact offspring success. “I mostly focus on native ground nesting bees, but also study the impact of chlorpyrifos leaf residues on nesting alfalfa leafcutter bees,” she said. “I am also interested in how nesting habitat availability shapes bee community composition and distribution across the landscape. My current focus is on sunflower fields, alfalfa seed production, and mosaic landscapes in serpentine chaparral.”

In addition to her PhD research, she participates in a variety of education outreach and conservation projects. She has presented lectures for the U.S. Fish and Wildlife Service as part of the Schoolyard Habitat Project; worked for the California Native Plant Society, documenting bee diversity in a threatened portion of Knowland Park in Oakland; and co-taught an undergraduate course focusing on current threats to pollinator populations and how to educate the general public to effect positive change.

Scampavia writes a bee blog, “Diadasia, The Lives of Other Bees,” at https://diadasia.wordpress.com/ that she launched in February 2012.

The Bee Symposium, sponsored by the Honey and Pollination Center and the UC Davis Department of Entomology and Nematology, featured keynote speaker Marla Spivak, Distinguished McKnight Professor, University of Minnesota and a 2010 MacArthur Fellow, who discussed "Helping Bees Stand on Their Own Six Feet." The symposium drew 360 people.

Entomology doctoral candidate Matthew Prebus of the Phil Ward lab, UC Davis Department of Entomology and Nematology, video-recorded the presentations and uploaded them today.

They are all on YouTube.

Marla Spivak: Protecting Pollinators

Amy Toth: Combined Effects of Viruses and Nutritional Stress on Honey Bee Health

Elina Niño: Best Management Practices to Support Honey Bee Health

Neal Williams: Enhancing Forage for Bees

Sarah Laird: The Bee Girl

Jake Reisdorf: Getting into Beekeeping- Thoughts from a 12-year-old Beekeeper

Katharina Ullmann: Project Integrated Crop Pollination

John Miller: Keeping Bees Healthy with Forage

Benjamin Sallman: Bee Informed Partnership

Gretchen LeBuhn: The Giant Sunflower Project

Christine Casey: Introduction to the Häagen Dazs Honey Bee Haven

 

"The Secret World of Insects" won't be so secret any more on Wednesday, June 3.

That's when a public exhibit and reception will take place to celebrate the work of Entomology 1 students, University of California, Davis.

The event takes place from 5 to 8 p.m., in the Third Space Art Collective, 946 Olive Drive.

The main instructor of Entomology 1 is Diane Ullman, professor of entomology, UC Davis Department of Entomology and Nematology, and an accomplished artist. She co-founded and co-directed the UC Davis Art/Science Fusion Program.

"We had four sections this quarter," Ullman said. Some 70 students participated.

1. Ceramics. The students created a screen-printed tile mosaic about evolution of the soapberry bug with the support and scientific advice of Jenella Loye and Scott Carroll of the Sharon Lawler lab, UC Davis Department of Entomology and Nematology. Carroll is the director of the UC Davis Institute for Contemporary Evolution. Also, this quarter, self-described rock artist Donna Billick, co-founder and former co-director of the UC Davis Art/Science Fusion Program, assisted the students.
2. Sculpture with reuse materials. The students made sculptural story boards about insects.
3. Painting and multimedia.The students did trip tic-like canvases about a diversity of insects.
4. Bioart. The students created insect drawings with fungi on agar.

Allison Simler, Vivian Ye and Anna Davidson (Evolution and Ecology, Design and Studio Art) served as teaching assistants.